JPS6115935A - Magnetic material for magnetic head - Google Patents

Abstract

PURPOSE:To obtain a magnetic material for a magnetic head showing high magnetic permeability in a weak magnetic field for measurement by preparing a preferentially amorphous alloy consisting of specified percentages of Co, Ni, Mo, Nb, B and Zr. CONSTITUTION:A molten alloy having a composition contg., by atom, 75-84% Co, 2-6% Ni, 5-10% Mo, 0.5-5% Nb, 0.1-5% B and 7-9% Zr and satisfying equations Mo%+Nb%+Zr%=13-20% and Co%+Ni%+Mo%+Nb%+B%+ Zr%=100% is made amorphous by very rapid cooling to obtain a magnetic material for a magnetic head having superior corrosion and wear resistances. The magnetic permeability of the magnetic material is very stable to heat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amorphous magnetic material for a magnetic head, which has various properties preferable as a soft magnetic material, particularly exhibits high magnetic permeability in a low measuring magnetic field, and The present invention relates to a magnetic material for a magnetic head that has excellent thermal stability of magnetic permeability, corrosion resistance, and wear resistance.

Background Art Conventionally, permalloy, sendust, ferrite, etc. have been used as core materials for magnetic heads, but permalloy has poor wear resistance, and sendust is brittle, so it requires a large number of man-hours to process into a thin plate. However, ferrite has various problems such as a low magnetic flux density of about 4000 to 5000G.

As a magnetic material for magnetic heads that solves this problem, an amorphous magnetic material has been developed that has favorable properties such as good soft magnetic properties and low current loss because it is a foil strip. Various improvements have been proposed to improve the wear resistance, increase magnetic flux density, and increase magnetic permeability of crystalline magnetic materials.

For example, JP-A-51-73920, JP-A-59-
The Go-
Although Fe si B-based amorphous magnetic materials have high magnetic flux density, their wear resistance is generally inferior to Sendust, and their thermal stability is such that their magnetic permeability initially shows a large value, but There has been a problem in that the temperature is significantly reduced by heating and holding at about 100° C. for bonding or molding, which are frequently used.

On the other hand, the applicant jointly proposed (Japanese Patent Application Laid-open No. 56-84439,
The cobalt-based amorphous alloy developed in JP-A-56-130449 has low magnetostriction, high magnetic permeability, and relatively high magnetic flux density, but it is difficult to obtain extremely high magnetic permeability using ordinary heat treatment methods. However, there was a problem in that only an extremely limited composition range could be used.

In addition, in the composition where the magnetostriction becomes small in the ω-7,r system,
An amorphous alloy for magnetic heads that contains Mo, B, and NL and has improved corrosion resistance, wear resistance, and saturation magnetic flux density has been proposed (Japanese Patent Application Laid-open No. 59-38349). Materials are needed.

By the way, when a magnetic head is assembled using the above-mentioned magnetic materials for magnetic heads and mounted on various recorders, etc., the generally desired high magnetic flux density material does not necessarily show good mounting characteristics, and the mounting characteristics are considered important. It has recently become known that impedance, bias current value, recording signal current value, playback frequency characteristics, playback sensitivity, etc. greatly depend on the magnetic permeability of the magnetic material used, especially in low magnetic fields. It is receiving particular attention.

When considering conventional magnetic materials from the viewpoint of improving the mounting characteristics of such magnetic heads, it is found that magnetic materials that simply have a high saturation magnetic flux density of over 10 kG cannot withstand high magnetic fields (101
110e or higher), but the magnetic permeability in a low magnetic field of about 11110e is extremely low compared to a high magnetic field, and for example, the reproduction sensitivity of a magnetic head for audio recording and reproduction is low. There was a problem.

Purpose of the Invention The present invention has various desirable properties as a soft magnetic material for a magnetic head, and exhibits especially high magnetic permeability in a low magnetic field so as to improve the mounting characteristics of a magnetic head. The objective is to create a magnetic material for magnetic heads that has excellent thermal stability in magnetic permeability, as well as corrosion resistance and wear resistance.

Structure and Effects of the Invention The present invention aims to create a magnetic material having soft magnetic properties preferable as a magnetic material for a magnetic head, and a magnetic material with small magnetostriction, which has Zr as the main component and Zr as the main amorphous element. Further studies have been conducted on crystalline materials, and from the perspective of improving the mounting characteristics of magnetic heads, we have developed materials that have an appropriate high magnetic flux density of about 6000 G or more, and in particular have a magnetic permeability in a low measurement magnetic field of about 0.1 m0e to 3 moθ. In order to obtain a magnetic material that exhibits an extremely high value and also has corrosion resistance, wear resistance, and excellent soft magnetic properties, we investigated various combinations of additive elements. , and B are useful for the above purpose, and 0
．． It was discovered that a magnetic permeability (1kl-1z) of 10,000 or more can be obtained in a low measurement magnetic field of about 1 m0e to 3 moe.

Furthermore, in detail, in the Co-Zr system, the magnetostriction is adjusted by adding Ni, the thermal stability of magnetic permeability and coercive force is increased by adding cold, and the permeability is improved by adding B and especially positive. It was discovered that the magnetic property could be improved, and studies were conducted for the purpose of improving various properties necessary for a magnetic material for a magnetic head, and the relationships among each component and their mutual content were determined and limited.

That is, this invention: Co 75 atomic% to 84 atomic%, Ni 2 atomic% to 6 atomic%, -5 at% to 10 at%.

Positive 0.5 at% to 5 at%.

Contains B O0 1 atomic % to 5 atomic %, Zr'-7 atomic % to 9 atomic %, Fb +N
It is a magnetic material for a magnetic head that satisfies b + Zr 13 atomic % to 20 atomic % and Ni 10 cold + positive + B + Zr = 100 atomic % and is preferentially amorphous.

The amorphous magnetic material according to the present invention can be made amorphous by ultra-quenching a molten metal having a predetermined composition, and can also be obtained by ultra-quenching from a gas phase, such as sputtering. , generally obtained in ribbons or films.

The amorphous ribbon or thin film according to the present invention is characterized by having low coercive force and magnetostriction, extremely high magnetic permeability, especially low magnetic field permeability, and providing magnetic properties that are thermally stable over time. Moreover, it is rich in corrosion resistance and wear resistance, is less susceptible to embrittlement than conventional amorphous magnetic materials containing large amounts of metalloid elements, and has excellent machinability such as punching and cutting. In addition, the electrical resistance is high at 120 to 140 μΩcm,
Moreover, since it can be obtained in the form of a ribbon or thin film with a thickness of about 100 to 50 weeks, it is ideal for core materials for magnetic heads, and is also suitable for small-sized magnetic core materials with good high frequency characteristics.

In addition, as shown in the examples, the amorphous magnetic material according to the present invention is characterized in that a water-based magnetic material whose crystallization temperature is higher than the Curie temperature is heated to a temperature range of not less than the crystallization temperature of the magnetic material and not more than the Curie temperature. The magnetic material is held for 1 to 100 minutes, and a magnetic field that rotates relative to the magnetic material is applied to the magnetic material.
By performing two-stage heat treatment for 0.3 to 3
Magnetic permeability (1kHz7) at moe measurement magnetic field is 1500
Improves from 0 to over 20,000.

Reason for component limitation CO is the main component in this composition, and 75 atomic % or more is required to obtain a magnetic flux density of about 6000 G or more, but if it exceeds 84 atomic %, the magnetic permeability at low measurement magnetic fields will not improve. Therefore, the content should be 75 at % to 84 at %, preferably 71 at % to 82 at %, and more preferably 77 at % to 8011i! Child% is good.

N1 is added to have the effect of reducing magnetostriction and making it negative without reducing the magnetic flux density, and within the content range of other component elements, the magnetostriction is substantially zero or slightly negative, and the magnetic flux density is 6000 (to make a magnetic material of 3 or more, it is necessary to add 2 at % or more, but if it is added in excess of 6 at %, the crystallization temperature and saturation magnetic flux density will decrease, so it is necessary to add 2 at % or more). The addition amount is atomic%.

MO is an element that makes magnetostriction negative and increases the thermal stability of magnetic permeability or coercive force, and is added, but if it is less than 5 at%, it will not have the above effect, and if it exceeds 10 at%, the magnetic flux density will decrease significantly. Therefore, the content is set to be 5 Wt % to 10 atomic %.

Nb has the ability to form an amorphous state next to Zr and B, and when included together with Zr and Nb, it has the effect of increasing the ability to form an amorphous state, makes magnetostriction negative, and improves magnetic permeability after heat treatment. It is added because it has the effect of promoting
If the amount is less than 0, the desired effect cannot be obtained, and even if it is added in an amount exceeding 5 atomic percent, the effect of improving magnetic properties cannot be obtained.
, 5 at% to 5 at%. Preferably, 1.
The range is preferably from 5 at.% to 5 at.%.

By containing B at the same time as lr, it is effective in increasing the ability of the material to form an amorphous state and reducing magnetic anisotropy.
The above effects can be obtained when the amount is at least 5 at%, preferably at least 0.5 at%, but adding more than 5 at% is not so effective in reducing magnetic anisotropy and causes a decrease in magnetic flux density.
Since it becomes easy to become brittle and also reduces the thermal stability of magnetism, the content is set to 0.1 atomic % to 5 atomic %. Further, the content is preferably 0.5 at % to 3 at %, and furthermore, in order to obtain extremely high thermal stability, the content is preferably 0.5 at % or more and 1 at % or less.

2 is the main amorphous element in the aqueous composition, and in order to easily become amorphous and obtain a stable amorphous state, 7
On the other hand, it is an element that makes the magnetostriction of the magnetic material positive, and in order to bring the magnetostriction as close to zero as possible, it needs to be contained at 9 atomic % or less, and 1 atomic % to 9 atomic %. %.

Also, Mo, Nb, and Zr are cue! J −mW'f
It has the effect of lowering r, but its total content is 13 at%
If it is less than 20 atomic %, the Curie temperature is high and sufficient magnetic permeability cannot be obtained even if heat treatment is performed, and if it exceeds 20 atomic %, the magnetic flux density will decrease significantly.
It is expressed as atomic %, preferably in the range of 15 atomic % to 18 atomic %.

The magnetic material according to the present invention contains the above-mentioned elements in various combinations, and contains 10 + Zr 13 at % to 20 at % and C < +
NL+cold+positive+B+Zy=100 atomic% is satisfied.

Example Figure 1 is a graph showing the relationship between the measured magnetic field and magnetic permeability in Example 1, and Figure 2 is a graph showing the relationship between the B element content and the coercive force difference and magnetization size depending on the measurement direction in Example 2. FIG. 3 is a graph showing the relationship between aging time and magnetic permeability reduction rate in Example 3. FIG. 4 is a graph showing the relationship between aging time and magnetic permeability reduction rate in Example 5.
Graph showing the relationship between r content, crystallization temperature, Curie temperature, and magnitude of magnetization. FIG. 5 is a graph showing the relationship between aging time and magnetic permeability in Example 6.

Ki medical Amorphous magnetic alloy according to the present invention: positive 1 (at%).

As 隘2 (at%), Co78.8-Ni3.2-Cold7-Nb2-B
O,95-Zy 8. As O5, comparative inversion 3 (at%), Co82.3-NLl-Ha 6.4-82-Zr
8.3, by ultra-quenching a molten metal with the following composition, a width of about 15 mm,
Manufacture a thin strip with a thickness of about 30ρ, 10mmφX 6mmφ
The rings were punched out, and after each was subjected to the optimum heat treatment and strain relief shown below, the magnetic permeability was measured at room temperature.

Heat treatment conditions: Invention No. 1 was heated at 500°C for 5 minutes and then water-cooled, and No. 2 was heated at 500°C for 5 minutes and then water-cooled, and then heated at 9.8 ko
Heat treatment was performed in a rotating magnetic field at 300° C. for 20 minutes in a magnetic field of e.

Comparative Example 1N&L3 was heated at 375°C in a magnetic field of 9.8 chives.
After heating for 30 minutes, it was cooled with water.

The measurement results of magnetic permeability are as shown in Figure 1.
At a measurement field as low as oe, the comparative inversion 3 is 400
Although only about 0 to 5,000 can be obtained, it can be seen that positive 1 of the present invention has a significantly high magnetic permeability of about 1oooo1 and positive 2 of about 20,000 or more.

Finally, a C-shaped recording/reproducing magnetic head was made using the above magnetic material, and it was attached to the same recorder to produce a 333Hz
When the reproduction sensitivity was measured, the magnetic head using the magnetic material of the second level of the present invention showed a value 5 dB higher than that of the magnetic head using the comparative inverted third magnetic material, indicating that the mounting characteristics were excellent. I understand.

Example 2 As an amorphous magnetic alloy according to the present invention, Co179. '
5-Xi-NL 3.2-t'b72Nb2-BX
-7, r 8.1 (aj%), and the molten metal with various X, i.e., day contents, was ultra-quenched to produce a ribbon about 15 mm wide and about 30 mm thick. , the absolute value of the difference between the coercive force HC in the longitudinal direction of various ribbons and the coercive force Hc in the width direction of the ribbon, 1, IHc //-HC
LI was measured.

Figure 2 shows the relationship between the above absolute value and the content of B. The above difference becomes smaller as the amount is added, becomes almost zero when 4 atomic % is added, and increases again when more is added. I understand.

In general, magnetic anisotropy exists even in amorphous soft magnetic materials, and magnetic anisotropy exists not only in ribbons produced by the roll method but also in ribbons produced by the sputtering method, and is measured with a torque meter. However, since it is possible to qualitatively estimate the magnitude of magnetic anisotropy based on the difference in coercive force depending on the direction of the ribbon,
From FIG. 2, it can be seen that B has the effect of reducing magnetic anisotropy even when added in an amount of about 5 atomic % or less.

Further, among the several types of ribbons mentioned above, those containing 8 at % or more of B were partially embrittled, and those containing 10 at % were entirely embrittled.

Therefore, B has the effect of reducing magnetic anisotropy, but
It can be seen that addition of 5 atomic % or less is preferable because as the content increases, embrittlement becomes more likely.

Example 3 In order to clarify the reason why cold was selected for the amorphous magnetic alloy of the present invention, m4 (at%): +9 to Co77-N12-t' was used as the amorphous magnetic alloy of the present invention.
-Nb1-B1-Zy9, as a comparative example, 11h5 (at%): Co77-Ni2-Cr9
-positive 1"E31-Zr 9, m6 (at%); G
o 77-NL2-V 9-t41-81-Zr 9,
A thin strip with a width of about 15++vn and a thickness of about 30ρ was produced by ultra-quenching the molten metal having the following composition. Rings of 10 mmφ x 6 mmφ were punched out and annealed for 10 minutes at a temperature above one Curie temperature and below 50°C below the crystallization temperature. The magnetic permeability of each sample (μ2: 1 kHz, 1
0 m0e) was measured using the transformer method, and then heated to 100°C.
The changes in magnetic permeability were investigated and shown in Figure 3.

As is clear from FIG. 3, the Co-Zr gold alloy containing copper is the most thermally stable magnetic material with little change in magnetic permeability.

Example 4 As an amorphous magnetic alloy according to the present invention, 7 (at%)
: Co79- NL3-1%? -flI&1I2-BO
,9-Zr 8.1, as a comparative example, 148 (at%); Co79-Ni3-Fb
9-B O09-Zy 8.1, a molten metal having a composition of
Rings of 10 mmφ x 6 mmφ were punched out, each sample was annealed at 500° C. for 5 minutes, and then heat treated in a rotating magnetic field of 350° C. for 20 minutes using a magnetic field of 9.8 koe.

The magnetic properties of the obtained sample, magnetic permeability μ2 (measured magnetic field 10
The frequency dependence and level characteristics of magnetic permeability (1kHz) of 10e) were measured and are shown in Table 1.

As is clear from Table 1, the magnetic flux densities of both alloys are almost the same, and the material rI&L8 also exhibits a considerably high magnetic permeability. It can be seen that the magnetic permeability is high over the entire frequency range, and that the magnetic permeability is particularly improved at low measurement magnetic fields.

This is because the material of the present invention has a part of 7 in the comparative example replaced with positive, and it is clear that positive is effective in improving magnetic permeability in an aqueous composition.

ctA87-X is shown below as an amorphous magnetic alloy according to the present invention.
I NL 2 t'bX Nb 2 B I
Zr 8 (at%), a series of molten metals with various compositions of X were ultra-quenched to form a material with a width of about 15 mm and a thickness of about 3 mm.
A thin ribbon of 0 ρ was produced, and the magnitude of magnetization, crystallization temperature, and Curie temperature were measured, and the relationship between the magnetization ratio and the Zr content (at%) is shown in FIG.

As is clear from Figure 4, the amount of protons t'b + Zr is 1
If it is less than 3 atomic %, the difference between the crystallization temperature and the Curie temperature will be as large as 100°C or more, and if it exceeds 20 atomic %, the magnitude of magnetization will decrease significantly.
It can be seen that the amount is preferably in the range of 13 atom % to 20 atom %, and more preferably in the range of 15 atom % to 18 atom %.

As an amorphous magnetic alloy according to this invention, lV & L9 (a
t%): Co78.8-NL3.2-Fb7-Fh2-B
Im with a composition of 0095-Zr 8.05 was ultra-quenched to produce a ribbon with a width of about 15 mm and a thickness of about 30 ρ.
Punch out a ring of mmφX 6nvnφ and make a sample of 5
After heating at 00° C. for 5 minutes, the sample was cooled with water and subjected to heat treatment in a rotating magnetic field at 300° C. for 20 minutes using a magnetic field of 15 koe.

The magnetic permeability μz (1 kHz and 100 kHz) of the obtained sample at a measurement magnetic field of 10110e was measured using a transformer method.

Next, the sample was heated and held at 120°C, and then cooled.
The magnetic permeability was measured at room temperature, and the degree of deterioration of the magnetic permeability due to heating and holding at 120° C. was measured, and the time dependence thereof is shown in FIG.

Generally, when assembling and processing a magnetic head from a thin plate or thin film core material, it is often heated at a temperature of 80°C to 150°C for about 3 to 6 hours. It can be seen that there is almost no deterioration of the magnetic properties even after passing through this process.

As an amorphous magnetic alloy according to the invention of Riko K.
%); C079-NL3-gate o7-Nb2-81-Zy8, positive 11 (at%): Co78.1-Ni 4.5-1'&8-1'40.
5-8 0.9- Zr 8, positive 12 (at%); Co80.5- Ni 2.1- Mo5-1'41.
4-F34-Zr7,rI&L13(at%): C080,5-NLO,5-1%8-NbO,5-
82-Zy 8,5, comparative example 1kL14 (at%)
As, Co 66-Fe4-Ru5-Cr3-8L4
-B 18, a molten metal with a composition of
．． A 5mm test piece was prepared, the tip was polished to 5R, and then subjected to an abrasion tester under the same conditions to perform an abrasion resistance test.
Obtained the results in the table.

The test conditions were as follows: A commercially available sliding tape coated with iron oxide was used, and the sliding speed was 4.75 cm 2 /sec.

The atmosphere was 40° C. and 70% humidity.

As is clear from the results in Table 2, the magnetic material for magnetic heads according to the present invention has a 6 to 12
It can be seen that the wear resistance is twice as good.

Table 2

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the measured magnetic field and magnetic permeability in Example 1, and Figure 2 is a graph showing the relationship between the content of eight elements and the coercive force difference and magnetization size depending on the measurement direction in Example 2. FIG. 3 is a graph showing the relationship between aging time and magnetic permeability reduction rate in Example 3. FIG. 4 is a graph showing the relationship between aging time and magnetic permeability reduction rate in Example 5. FIG. FIG. 5 is a graph showing the relationship between aging time and magnetic permeability in Example 6. Applicant Sumitomo Special Metals Co., Ltd. Figure 1 Measured magnetic field (MOE) Figure 2 B atoms (chi) Figure 3 Large aging time (minutes) Figure 4

Claims (1)

[Claims] 1 Co: 75 at.% to 84 at.%, Ni: 2 at.% to 6 at.%, Mo: 5 at.% to 10 at.%, Nb: 0.5 at.% to 5 at.%, B: 0.1 atom. % to 5 atom%, Zr 7 atom% to 9 atom%, Mo+Nb+Zr 13 atom% to 20 atom%, and Co+
Ni+Mo+Nb+B+Zr=100 atomic%,
A magnetic material for magnetic heads that is preferentially amorphous. 2. The magnetic material for a magnetic head according to claim 1, which contains 0.5 to 3 at% of B. 3. The magnetic material for a magnetic head according to claim 1, which contains 0.5 at.% to 1 at.% of B.